gir: Parse graphene-config.h
gir: Parse graphene-config.h

We're generating introspection data but ignoring the SIMD types, even
though we have a workaround for the introspection scanner to assume that
the SIMD types are sized as four floats.

The SIMD API is still not introspected, but that's intentional: it's all
inlined, and it's too much of a low level API for anything but C.

ebassi/graphene,ebassi/graphene